WO2024054357A1 - Mosaïque d'affichage à visibilité de joint réduite - Google Patents

Mosaïque d'affichage à visibilité de joint réduite Download PDF

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Publication number
WO2024054357A1
WO2024054357A1 PCT/US2023/031007 US2023031007W WO2024054357A1 WO 2024054357 A1 WO2024054357 A1 WO 2024054357A1 US 2023031007 W US2023031007 W US 2023031007W WO 2024054357 A1 WO2024054357 A1 WO 2024054357A1
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Prior art keywords
major surface
coating material
coated
edge
reflectivity
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PCT/US2023/031007
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English (en)
Inventor
Alexander Lee CUNO
Dae Youn Kim
Kyung-Jin Lee
Shenping Li
Dong Keun Shin
Hong Yoon
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Corning Incorporated
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Publication of WO2024054357A1 publication Critical patent/WO2024054357A1/fr

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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G09F9/33—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being semiconductor devices, e.g. diodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
    • H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
    • H01L25/04—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
    • H01L25/075—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00
    • H01L25/0753—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00 the devices being arranged next to each other

Definitions

  • the present disclosure relates to optical display devices, and in particular tiled optical display devices having reduced visibility at the gaps between individual display panels of the tiled optical display devices.
  • an optical display device comprising a base plate comprising a first major surface coated with a first coating material and a second major surface opposite the first major surface, a first substrate comprising a third major surface, a fourth major surface opposite the third major surface and disposed on the first coating material, and a first edge surface disposed between the third major surface and the fourth major surface.
  • the optical display device may further comprise a second substrate comprising a fifth major surface, a sixth major surface opposite the fifth major surface and disposed on the first coating material, and a second edge surface disposed between the fifth major surface and the sixth major surface and extending adjacent the first edge surface such that the first edge surface and the second edge surface are separated by a gap.
  • a first surface portion of the third major surface adjacent to and extending along the gap may be coated with a second coating material different than the first coating material, and at least a portion of a second surface portion of the third major surface adjacent the first surface portion is coated with a third coating material different than the second coating material.
  • a reflectivity of the first major surface coated with the first coating material of the optical display device of the first aspect is less than a reflectivity of the first surface portion coated with the second coating material.
  • a reflectivity of the first major surface coated with the first coating material of the optical display device of the first aspect may be at least 50% less than a reflectivity of the first surface portion coated with the second coating material.
  • a reflectivity of the first major surface coated with the first coating material of the optical display device of the first aspect may be at least 75% less than a reflectivity of the first surface portion coated with the second coating material.
  • a scattering factor n e of the first surface portion coated with the second coating material of the optical display device of any one of the first through the fourth aspects may be equal to or less than a scattering factor ⁇ J S of the second surface portion coated with the third coating material.
  • a reflectivity of the first surface portion coated with the second coating material of the optical display device of the first aspect may be greater than a reflectivity of the second surface portion coated with the third coating material.
  • a third surface portion of the fifth major surface adjacent to and extending along the gap of the optical display device of the first aspect may be coated with the second coating material, and at least a portion of the fourth surface portion of the fifth major surface adjacent the third surface portion is coated with the third coating material
  • the first surface portion of the optical display device of the seventh aspect may comprise a first chamfer surface and the third surface portion may comprise a second chamfer surface.
  • at least a portion of the second surface portion and at least a portion of the fourth surface portion of the optical display device of the eighth aspect may be coated with the second coating material.
  • a width of the gap between the first edge surface and the second edge surface of the optical display device of the first aspect may increase in a direction from the third major surface toward the base plate.
  • a width of the gap between the first edge surface and the second edge surface of the optical display device of the first aspect may decrease in a direction from the third major surface toward the base plate.
  • the first edge surface of the optical display device of the first aspect may comprise an arcuate surface.
  • the first edge surface and the second edge surface of the optical display device of any one of the first aspect through the twelfth aspects may be coated with the second coating material.
  • the third major surface of the optical display device of any one of the first through the thirteenth aspect may comprise a plurality of light emitting diodes disposed thereon.
  • an optical display device comprising a base plate comprising a first major surface coated with a first coating material and a second major surface opposite the first major surface, a first substrate comprising a third major surface, a fourth major surface opposite the third major surface and disposed on the first coating material, and a first edge surface disposed between the third major surface and the fourth major surface, and a second substrate comprising a fifth major surface, a sixth major surface opposite the fifth major surface and disposed on the first coating material, and a second edge surface disposed between the fifth major surface and the sixth major surface and extending adjacent the first edge surface such that the first edge surface and the second edge surface are separated by a gap.
  • the third major surface may be coated with a second coating material different than the first coating material, a surface roughness of the first major surface coated with the first coating material may be equal to a surface roughness of the third major surface coated with the second coating material, and a reflectivity of the first major surface coated with the first coating material may be greater than a reflectivity of the third major surface coated with the second coating material.
  • the third major surface of the optical display device of the fifteenth aspect may comprise a plurality of light emitting diodes disposed thereon.
  • the reflectivity of the first major surface coated with the first coating material of the optical display device of the fifteenth or the sixteenth aspects may be less than 2 times the reflectivity of the third major surface coated with the second coating material.
  • the reflectivity of the first major surface coated with the first coating material of the optical display device of the seventeenth aspects may be in a range from about 5% to about 10%.
  • an optical display device comprising a base plate comprising a first major surface coated with a first coating material and a second major surface opposite the first major surface, a first substrate comprising a third major surface coated with a second coating material, a fourth major surface opposite the third major surface and disposed on the first coating material, and a first edge surface disposed between the third major surface and the fourth major surface, a second substrate comprising a fifth major surface coated with the second coating material, a sixth major surface opposite the fifth major surface and disposed on the first coating material, and a second edge surface disposed between the fifth major surface and the sixth major surface and extending adjacent the first edge surface such that the first edge surface and the second edge surface are separated by a gap.
  • a reflectivity of the first major surface coated with the first coating material may be greater than a reflectivity of the third major surface or the second major surface coated with the second coating material.
  • the reflectivity of the base plate of the optical display device of the nineteenth aspect may be less than 2 times the reflectivity of at least one of the third major surface or the fifth major surface coated with the second coating material.
  • At least one of the first edge surface or the second edge surface of the optical display device of the nineteenth or the twentieth aspects may be coated with the second coating material.
  • the base plate, the first substrate or the second substrate of the optical display devices of any one of the preceding aspects may comprise glass.
  • any one or more of the first substrate, the second substrate, or the base plate of the optical display devices disclosed herein may comprise glass, for example a silica-based glass, e.g., an aluminosilicate glass, such as an aluminoboro silicate glass.
  • a silica-based glass e.g., an aluminosilicate glass, such as an aluminoboro silicate glass.
  • FIG. 1 is a plot graphically illustrating the intensity of light reflected from an exemplary tiled display as a function of position across several tiles of the display, including across a gap between the several tiles;
  • FIG. 2 is a cross-sectional schematic view of an exemplary tiled display comprising a plurality of LED boards, a base plate to which LED boards 12 comprising light emitting diodes 16 disposed thereon are attached, and a cover fdter, and illustrates view angle;
  • FIG. 3 is a plot of the absolute value of Seam Visibility factor (SVF) as a function of base plate reflectivity Ruase Plate obtained from experiments;
  • FIG. 4 is a plot showing a Gaussian profile of surface scattering a from an exemplary tiled display as a function of scattering factor a in degrees;
  • FIG. 5A is a cross-sectional view of an exemplary tiled display according to embodiments of the present disclosure.
  • FIG. 5B is a close-up view of the exemplary tiled display of FIG. 5A;
  • FIG. 6 is a cross-sectional view of another exemplary tiled display according to embodiments of the present disclosure.
  • FIG. 7 is a cross-sectional view of an exemplary tiled display comprising chamfer surfaces according to embodiments of the present disclosure
  • FIG. 8 is a cross-sectional view of another exemplary tiled display comprising chamfer surfaces according to embodiments of the present disclosure
  • FIG. 9 is a cross-sectional view of still another exemplary tiled display comprising chamfer surfaces according to embodiments of the present disclosure.
  • FIG. 10 is a cross-sectional view of yet another exemplary tiled display comprising chamfer surfaces according to embodiments of the present disclosure
  • FIG. 11 is a cross-sectional view of a exemplary tiled display comprising display tiles with angled edge surfaces defining a gap therebetween according to embodiments of the present disclosure
  • FIG. 12 is a cross-sectional view of another exemplary tiled display comprising display tiles with angled edge surfaces defining a gap therebetween according to embodiments of the present disclosure
  • FIG. 13 is a cross-sectional view of another exemplary tiled display comprising display tiles with arcuate edge surfaces defining a gap therebetween according to embodiments of the present disclosure
  • FIG. 14 is a schematic view of a lighting set-up for experiments conducted according to embodiments disclosed herein;
  • FIG. 15 is a plot showing corresponding intensity distributions for chamfer surface reflectivities over a range from 3% to 10%;
  • FIG. 18 is a plot showing modeled seam visibility factor SVF as a fraction of scattering factor for all surfaces of an exemplary tiled display for a normal viewing angle
  • FIG. 20 a cross-sectional view of a representative tiled display device used for an experimental study on the effect of near-edge LED board coating on tiling seam visibility according to embodiments of the present disclosure
  • FIG. 21 is a plot showing the reflection spectra of inks used to coat components of exemplary tiled display devices in according to embodiments of the present disclosure
  • FIG. 22 is a cross-sectional view of a representative tiled device used as an experimental reference device according to embodiments of the present disclosure
  • FIG. 23 is a plot showing the measured cross-sectional intensity distributions of the tiling seam for the reference tiled display of FIG. 22;
  • FIG. 24 is a plot showing the measured cross-sectional intensity distributions of the tiling seam for the display device of FIG. 20;
  • FIG. 25 is a plot showing curves of measured SVF as a function of viewing angle for the reference case (line with circles) of FIG. 22 and the case under experimental study (line with squares) of FIG. 20.
  • the term “about” means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art.
  • Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value to the other particular value. Similarly, when values are expressed as approximations by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
  • substantially is intended to note that a described feature is equal or approximately equal to a value or description.
  • a “substantially planar” surface is intended to denote a surface that is planar or approximately planar.
  • substantially is intended to denote that two values are equal or approximately equal.
  • “substantially” may denote values within about 10% of each other, such as within about 5% of each other, within about 2% of each other, or within about 1 % of each other.
  • the terms “gap” and “seam” are synonymous and refer to the region separating individual and immediately adjacent display panels, for example individual display panels (e.g., LED boards) disposed on a base plate.
  • the manufacture of large area displays is more easily accomplished by tiling multiple small displays together in vertical and/or horizontal arrays, wherein the image to be displayed can be segmented across the multiple displays.
  • multiple thin display panels can be arranged on a common base plate to form a larger tiled display.
  • a small gap may exist between adjacent edge surfaces of the individual display panels of the tiled display.
  • this gap may be on the order of a pixel width apart (e.g., about 50 micrometers or smaller), the human eye is capable of discerning such an image discontinuity, particularly when displayed in a regular geometric array (e.g., straight lines, for example a rectangular pattern of individual display panels).
  • a regular geometric array e.g., straight lines, for example a rectangular pattern of individual display panels.
  • seam visibility depends at least on the degree to which ambient light incident on the tiled display is reflected from the individual display panels compared to the light reflected from the base plate through the intervening gap(s) between the individual display panels.
  • seam visibility can be decreased by adjusting reflectance of the individual display panels relative to the base plate to be greater than the reflectance of the base plate to which the individual display panels are mounted. This can be accomplished by modifying the reflectance of the individual display panels, modifying the reflectance of the base plate, or modifying both the individual display panels and the base plate.
  • SVF WG/(WFWHF) x A/Ib (1)
  • SVF represents the seam visibility factor
  • WG represents the distance between the adjacent light (e.g., LED) boards (e.g., the gap Gtherebetween - see FIG. 2)
  • WFWHM represents the width of the cross-sectional intensity distribution of a tiled device image at the gap at one half the the maximum intensity A of the intensity distribution
  • lb is the base intensity of the cross-sectional intensity distribution (e.g., spaced away from the gap).
  • FIG. 1 is a plot graphically illustrating several parameters of Equation (1), specifically lb, WFWHM, and A.
  • the dip in the displayed curve represents the location of the gap G between LED boards.
  • the light scattering property of a surface relative to a coated surface can be described by a Gaussian scattering function represented by the following equation:
  • Equation (3) if the reflectivity RIFD Board of the LED board is equal to the reflectivity Rsase Plate of the base plate, SVF is zero for a 0-degree view angle p v .
  • SVF is zero for a 0-degree view angle p v .
  • not all light reaching the base plate can be reflected back to reach the viewer at least because of scattering of light incident on the base plate. Consequently, some light may be trapped in the gap between LED boards and/or light may be reflected from the back plate at a non-normal angle. Light escaping at a non-normal angle may intersect side walls of the display panels.
  • the light escaping factor a is relative to the scattering factor of the base surface, which is in turn relative to the base plate surface roughness and is defined as the outcoupling ratio from the seam geometry.
  • a light escaping factor of 1.0 means 100% light is outcoupled without any loss of incoming light, while a light escaping value of 0.5 indicates a 50% light loss inside the gap due to absorption of scattered light at the side wall(s) defining the seam.
  • the light escaping factor is expected to be the range of 0.5 to 1.0 assuming a Gaussian profile of scattered light.
  • FIG. 2 shows a cross-sectional schematic view of an exemplary tiled display 10 comprising a plurality of LED boards 12, abase plate 14 to which LED boards 12 comprising light emitting diodes 16 disposed thereon are attached, and a cover filter 18.
  • Cover filter 18 can function to reduce surface reflection of the display, enhance contrast ratio, adjust displayed color of the display, and/or protect the display.
  • the light boards may comprise glass, for example, and without limitation, a silicate glass such as an alkali-free borosilicate glass, or an alumino-borosilicate glass, or any other glass suitable for the manufacture of optical display devices.
  • the base plate may comprise a glass material, similar to or different from the glass of the LED boards.
  • the base plate and/or the LED boards may comprise a polymer material, for example a phenolic material.
  • a viewer of the tiled display is designated by the reference numeral 20 and is shown observing the tiled display at a view angle p v relative to a normal 22 to the tiled display 10 (e.g., cover fdter 18).
  • the figure illustrates light trapping within gap G due to scattering at the base plate surface.
  • the LED boards had a thickness t s of 500 micrometers (pm) and a width WG of gap G between adjacent light boards was 50 pm.
  • the critical view angle (Lc represents the angle within which light can escape the gap (e.g., clear the edges of the adjacent LED boards) and for the current example is approximately 3 ° ⁇ 1 ° .
  • the reflectance RLED Board of the LED boards is equal to the reflectivity of the base plate Rsase Plate in this example, the seam remains visible (as if the surface of the base plate has a different surface roughness, thus a different scattering factor, which results in different reflectivity values).
  • the reflectivity of the base plate should be slightly greater than the reflectivity of the LED boards if the base plate and the LED boards have the same surface roughness (or same scattering factor).
  • the polymer was determined to contain C, O, F, Mg and Si in amounts by weight of about 23.6%, 68.2%, 2.4%, 2.7% and 3.1%, respectively, by Scanning Electron Microscopy with Energy Dispersive X-ray analysis (SEM-EDX).
  • SEM-EDX Scanning Electron Microscopy with Energy Dispersive X-ray analysis
  • the coating was applied by spray coating. In the instance of LED boards with 5.2% reflectivity, the boards were coated with a thermally cured phenoxy resin comprising carbon black powder.
  • the coating material was deposited on the LED boards by screen printing.
  • the resin contained C, O, Si and Ca in amounts of about 26.3%, 71.6%, 0.85 and 1.13%, respectively, again determined by SEM-EDX. Edge surfaces of the LED boards were either coated or left bare (uncoated).
  • the transmittance of the cover filter was 57%, the viewing angle was 0°, and there was a 50 pm gap (WG) between adjacent LED boards.
  • the LED boards were illuminated by a 380-lux ambient light normal to the surface of the boards, measured by a Testo 540 light meter at the surface of the LED boards.
  • the light escaping factor a was assumed to be 0.5 and 1.0, respectively.
  • the LED boards had a surface roughness after coating as indicated in Table 2. Surface roughness was measured using a confocal laser scanning microscope. Samples with an edge surface reflectivity of 4.0% were not edge coated.
  • FIG. 3 is a plot of the absolute value of SVF as a function of base plate reflectivity Rfiase Plate obtained from the preceding experiments, where curve 20 represents an LED board reflectivity Board of 5.2% and abase plate reflectivity RsasePiate of 4.0%, curve 22 represents an LED board reflectivity Board of 5.2% and a base plate reflectivity RBase Plate of 5.2% , and curve 24 represents an LED board reflectivity RLED Board of 3.9% and a base plate reflectivity Rnase Plate of 4.0%.
  • Range 26 represents the approximate base plate reflectivity over which SVF is essentially zero.
  • the three lines 20, 22, and 24 come from the data in Table 1.
  • FIG. 3 shows the inflection points of
  • ⁇ 0 comes close to R(Base Plate). If the seam region surfaces are rough, trapping of incoming light becomes more pronounced, and thus less light escapes. Based on experiments and theoretical estimation, the light escaping factor is in a range between 0.5 and 1.0, which corresponds to 5% ⁇ R(SVF 0) ⁇ 10%
  • FIG. 4 is a plot showing a Gaussian profde of surface scattering as a function of scattering factor a in degrees. The shaded region depicts low to moderate scattering in the seam area.
  • FIG. 5 A is a cross-sectional view of a tiled display 100 and FIG. 5B is a closeup view of portion B from FIG. 5 A.
  • Tiled display 100 comprises a base plate 102 including a first major surface 104 and a second major surface 106 opposite first major surface 104.
  • First and second major surfaces 104, 106 may be parallel surfaces.
  • First major surface 104 may comprise a first coating material 108 disposed thereon.
  • First coating material 108 comprises a first reflectivity Rb and a first scattering factor Ob (see Equation (1)).
  • Tiled display 100 further comprises a first LED board (substrate) 110 comprising a third major surface 112 and a fourth major surface 114 opposite third major surface 112.
  • Third and fourth major surfaces 112, 114 may be parallel surfaces.
  • Fourth major surface 114 of first LED board 110 is disposed on base plate first major surface 104 overtop first coating material 108.
  • a first edge surface 116 of first LED board 110 is disposed between third major surface 112 and fourth major surface 114 and joins third major surface 112 and fourth major surface 114.
  • First edge surface 116 may be orthogonal to third and fourth major surfaces 112, 114.
  • third major surface 112 may include aplurality of light emitting diodes (e.g., LEDs, microLEDs) disposed thereon.
  • Tiled display 100 still further comprises a second LED board (substrate) 118 comprising a fifth major surface 120 and a sixth major surface 122 opposite fifth major surface 120.
  • Fifth and sixth major surfaces 120, 122 may be parallel surfaces.
  • Sixth major surface 122 is disposed on base plate first major surface 104 overtop first coating material 108.
  • a second edge surface 124 is disposed between fifth major surface 120 and sixth major surface 122 and joins fifth major surface 120 and sixth major surface 122. Second edge surface 124 may be orthogonal to fifth and sixth major surfaces 120, 122.
  • fifth major surface 120 may include aplurality of light emitting diodes (e.g., LEDs, microLEDs) disposed thereon.
  • First LED board 110 and second LED board 118 are arranged such that a gap G comprising a width WG separates first edge surface 116 from second edge surface 124. That is, first and second edge surfaces 116, 124 are adjacent edge surfaces separated by gap G. In this context, adjacent means first and second edge surfacesl l6, 124 are directly opposite one another with no intervening structure.
  • Gap G may be a uniform gap, wherein first and second edge surfaces 116, 124 are parallel edge surfaces separated uniformly by width WG.
  • third major surface 112 may comprise a first surface portion 126 and a second surface portion 128 adjacent first surface portion 126. That is, first surface portion 126 may be a near-edge surface portion extending along gap G and having a uniform width W ei extending from the intersection of third major surface 112 and first edge surface 116. Second surface portion 128 extends over the remainder of third major surface 112, for example from first surface portion 126 in a direction away from gap G.
  • fifth major surface 120 may comprise a third surface portion 130 and a fourth surface portion 132 adjacent third surface portion 130.
  • Third surface portion 130 may likewise be a near-edge surface portion extending along gap G and having a uniform width W e 2 extending away from the intersection of fifth major surface 120 and second edge surface 124.
  • W ei may be equal to W e 2.
  • Fourth surface portion 132 may extend over the remainder of fifth major surface 120, for example from third surface portion 130 in a direction away from gap G.
  • first surface portion 126 of third major surface 112 may be coated with a second coating material 134 and second surface portion 128 may be coated with a third coating material 136.
  • third surface portion 130 of fifth major surface 120 may be coated with second coating material 134 and fourth surface portion 132 of fifth major surface 120 may be coated with third coating material 136.
  • Second coating material 134 comprises a second reflectivity Re and a second scattering factor n e
  • third coating material 136 comprises a third reflectivity Rs and a third scattering factor ⁇ J S .
  • first and second edge surfaces 116, 124 are uncoated.
  • FIG. 6 depicts a tiled display 200 similar to tiled display 100 of FIGS. 5A and 5B, with the exception that, in addition to near-edge surface portions 126, 130 of third and fifth major surfaces 112, 120 bordering first and second edge surfaces 116, 124, respectively, first and second edge surfaces 116, 124 may also be coated with second coating material 134 such that second coating material 134 extends continuously over first and third surface portions 126, 130 and over first and second edge surfaces 116, 124.
  • FIG. 7 illustrates a portion of another tiled display 300 similar to tiled display 100 shown in FIG. 5A-5B, with the exception that first surface portion 126 of third major surface 112 and third surface portion 130 of fifth major surface 120 each comprise a chamfer surface.
  • chamfer surface 140 of first surface portion 126 of third major surface 112 forms an angle a ci relative to the plane of third major surface 112
  • third surface portion 130 of fifth major surface 120 comprises a second chamfer surface 142 forming an angle a C 2 relative to the plane of fifth major surface 120.
  • the entirety of first surface portion 126 comprises first chamfer surface 140 and the entirety of third surface portion 130 comprises the second chamfer surface 142.
  • FIG. 7 illustrates a portion of another tiled display 300 similar to tiled display 100 shown in FIG. 5A-5B, with the exception that first surface portion 126 of third major surface 112 and third surface portion 130 of fifth major surface 120 each comprise a chamfer surface.
  • first surface portion 126 e.g., first chamfer surface 140
  • third surface portion 130 e.g., second chamfer surface 142
  • second coating material 134 coating at least a portion of second surface portion 128 and at least a portion of fourth surface portion 132 coats the respective at least a portion 128, 132 along a strip of the at least a portion 128, 132 parallel with gap G, wherein a width of the strip is designated in FIG. 7 as W e .
  • At least a portion of an unchamfered portion of third major surface 112 and fifth major surface 120 are coated with second coating material 134.
  • the width of the unchamfered surfaces coated with second coating material 134 taken parallel to third major surface 112 and fifth major surface 120 is designated W c .
  • At least a portion of second surface portion 128 and at least a portion of fourth surface portion 132 may each be coated with third coating material 136.
  • at least a portion of second surface portion 128 and at least a portion of fourth surface portion 132 are coated with second coating material 134, and the remainder of second surface portion 128 and fourth surface portion 132 are coated with third coating material 136.
  • first and second edge surfaces 116, 124 are also coated with second coating material 134.
  • FIG. 9 depicts another tiled display 500 similar to the tiled display of FIG. 8 with the exception that second surface portion 128 and fourth surface portion 132 are not coated with second coating material 134.
  • first surface portion 126 and third surface portion 130 are comprised entirely of chamfer surface 140 and chamfer surface 142, respectively, and first chamfer surface 140 and second chamfer surface 142 are coated with second coating material 134.
  • Second surface portion 128 and fourth surface portion 132 are coated with third coating material 136.
  • First and second edge surfaces 116, 124 of first and second LED boards 110, 118 are uncoated.
  • FIG. 10 depicts another tiled display 600 similar to tiled display 500, with the exception that first and second edge surfaces 116, 124 are coated with second coating material 134 in addition to chamfer surfaces 140, 142 being coated with second coating material 134.
  • FIGS. 11-13 show other embodiments of tiled displays incorporating engineered edges. That is, the light boards have edges exhibiting other than planar edge surfaces orthogonal to the major surfaces of the substrates.
  • FIG. 11 depicts atiled display device 700 similar to tiled display device 100 but comprising edge surfaces 116, 124 that slope downward from first and third major surfaces and outward (away from a centerline 125 of gap G) such that the width WG of gap G increases in a direction from third major surface 112 toward first major surface 104 of base plate 102 (in the direction of arrow 144).
  • First and second edge surfaces 116, 124 form an angle ([> with first major surface 104 of base plate 102.
  • Angle ([> (external to first and second edge surfaces 116, 124) is an acute angle in this embodiment.
  • edge surfaces 116 and/or 124 may be fully or partially coated with second coating material 134.
  • FIG. 12 depicts atiled display device 800 similar to tiled display device 100 but where edge surfaces 116, 124 slope downward and inward such that the width WG of gap G decreases in a direction from third major surface 112 toward first major surface 104 of base plate 102 (in the direction of arrow 144).
  • First and second edge surfaces form an obtuse angle ([> with first major surface 104 of base plate 102.
  • edge surfaces 116 and/or 124 may be fully or partially coated with second coating material 134.
  • FIG. 13 depicts a tiled display device 900 similar to tiled display device 100 but where LED boards 110, 118 have arcuate (e.g., rounded, bullnose) edge surfaces.
  • the edge surfaces 116, 124 may be fully or partially coated with first coating material 134, whereas the third and fourth major surfaces of LED boards 110, 118 may be fully or partially coated with third coating material 136.
  • the optimal reflectivity of the near-edge substrate surface coating (e.g., coating material 134 applied to first and third surface portions 126, 130) for suppressing tiling seam visibility can be expressed as,
  • Re (( ⁇ (WG ⁇ c+Wejj/CfeXOe/Osy-Rs - ((Cfb/Cf c )-(W G /(2(W c + W e ))-(Oe/o S )yRb, (4)
  • Re and n e represent reflectivity and scattering factor of the near-edge substrate surface coating , respectively, for the first and third surface portions 126, 130
  • Rs and ⁇ J S represent reflectivity and scattering factor of the second and fourth substrate surfaces 128, 132
  • Rb and Ob represent reflectivity and scattering factor of the coated base surface 104 in the gap G
  • WG is the width of gap G between the substrates
  • W c and W e are widths of the substrate chamfer surfaces and/or the coated near-edge first and second surface portions 126, 130.
  • the exponent y is a constant equal to 1.7 and Cfb is a correction factor for the tiling gap.
  • This correction factor represents the portion of light reflected from base surface 104 (e.g., coating material first coating material 108) trapped in gap G between the LED boards relative to the gap width, LED board thickness t s , chamfer angle a c , and the base and edge surface properties. Accordingly, Cfb is less than 1.
  • Cf c is a correction factor that relates to chamfer angle and the ratio of W c /W e .
  • the intensity of light reflected by the base plate surface should be less than the intensity of light reflected by the LED board surfaces (i.e., in the right side of Eq. (4), the second term should be much smaller than the first term).
  • a reflectivity of the first major surface coated with the first coating material may be at least 50% less than a reflectivity of the first surface portion coated with the second coating material, such as at least 75% less than a reflectivity of the first surface portion coated with the second coating material.
  • Equation (4) becomes
  • Equation (4) and Equation (5) conditions needed for the second term to be much less than the first term can be achieved by (1) Rb — > 0; (2) Ob » o e , and/or; (3) (W c + We) » W G .
  • FIG. 14 The modeling setup for ray tracing is shown in FIG. 14 and comprises a tiled display device (tiled display device 600 shown) and three ambient light sources, a first, broad array light source 1000, a second light source 1002 arranged to illuminate the first chamfer surface 140 (upper chamfer surface in the figure) and a third light source 1004 arranged to illuminate the second chamfer surface 142 (lower chamfer surface in the figure).
  • An observer 1006 of the display device was assumed to be arranged at a position normal to the display device along line 1008 extending through the gap between the display substrates.
  • FIG. 15 is a plot showing corresponding intensity distributions for chamfer surface reflectivities over a range from 3% to 10%. The data show tiling seam visibility varied with chamfer surface reflectivity, with the least tiling seam visibility achieved with a chamfer surface reflectivity slightly greater than about 5% (e.g., between about 5% and about 6%).
  • the line represents analytical results calculated from Equation (4), and the circles are ray-tracing modeling results.
  • the analytical prediction (line) agrees with the results of the ray-tracing modeling (circles).
  • Equation (4) or Equation (5) implies the light intensity observed by a viewer collected from the tiling gap area (gap + near-edge area) equals the light intensity from a noseam substrate surface with the same area.
  • the reflected incident ambient light should be scattered into a certain solid angle, implying the near-edge LED board surface should have a certain scattering (e.g., scattering factor > 0).
  • the threshold for the scattering factor of the near-edge LED board surface two example cases that satisfy Equation (5) and Equation (4), respectively, were modeled.
  • FIG. 18 is a plot showing the modeled seam visibility factor SVF as a fraction of scattering factor for all surfaces for a normal (i.e., 90 degree) viewing angle.
  • Line 1100 and line 1102 represent the modeling results of the first and second cases, respectively.
  • line 1100 represents SVF for base plate surfaces and nearby-tiling -edge LED board surfaces having reflectivities of 0%, and 11%, respectively.
  • Line 1102 represents SVF for base plate surfaces and nearby-tiling-edge LED board surfaces having reflectivities of 2.5%, and 8.5%, respectively.
  • the squares represent SVF for light reflected from the tiling seam area of the first case (line 1100) for a scattering factor of 0 degrees, 0.29 degrees, 0.57 degrees, and 1.15 degrees from left to right. It can be seen that with an increase of scattering factor, the reflected light is more evenly distributed over the tiling seam area. Both cases show that when the scattering factor of the chamfer surface (or near-edge LED board surface) is larger than 1 degree, the reflected light can be evenly distributed over the tiling seam area.
  • the second case simulated is the schematic shown in FIG. 6, in which the tiling edges of the two substrates are without chamfers, and the widths W e i, W e 2 of the near-edge substrate surface coatings are 50 pm. Table 4 gives the modeling parameters for this case.
  • the optimal reflectivity derived from intensity distributions of light reflected from the tiling seam area achieved by ray-tracing modeling when the ratio of scattering factors (o e /c s ) is 0.67, 0.82, 0.93, and 1.1, respectively, are shown as discrete points in FIG. 19.
  • a scattering factor n e of the first surface portion coated with the second coating material should be equal to or less than a scattering factor ⁇ J S of the second surface portion coated with the third coating material.
  • the correction factor C& was found to be 0.8.
  • the analytical result (line) of the second modeled case is in good agreement with the results of ray-tracing modeling (circles).
  • the tiled device with a gap width WG of 50 pm consisted of one base plate 102 and two glass substrates 110, 118 (0.4 mm thick Coming® Lotus NXT glass) that were cut by laser and represented two LED boards. There were no electronic devices (e.g., LEDs) on the substrates.
  • the edge surfaces 116, 124 and near-edge substrate surfaces were coated with a black ink A (Media NM-M1) having a reflectivity of about 7.3% at 550 nm. Meanwhile, the other three edges of the substrate were without coating.
  • FIG. 21 is a plot showing the reflection spectra of the inks A and B.
  • FIG. 22 is a cross- sectional view of the tiled device for the reference measurement.
  • FIG. 23 is a plot showing the measured cross-sectional intensity distributions of the tiling seam for the reference case and FIG. 24 shows the measured cross-sectional intensity distributions of the tiling seam for the case under study in which the tiling edge and nearby- tiling-edge substrate surfaces were coated with black ink B for a viewing angle from 0 degrees to about 50 degrees with a step of 10 degrees.
  • FIG. 25 is a plot showing the curves of measured SVF as a function of viewing angle for the reference case (line with circles) and the case under study (line with squares) .
  • the data show that tiling seam visibility can be suppressed by coating the near-edge substrate surface (e.g., LED board) with a material (e.g., black ink B) having a greater reflectivity than the coating material (e.g., black ink A) of the other areas of the substrate surface for viewing angles from about 10 degree to about 50 degrees.
  • a material e.g., black ink B
  • black ink A the coating material of the other areas of the substrate surface for viewing angles from about 10 degree to about 50 degrees.
  • the lack of improvement in SVF at a normal viewing angle is believed to be a consequence of the base surface reflectivity not being close to zero (in the right side of Equation (4), i.e., the second term is not much smaller than the first term), which results in a lowering of SVF of the zeroviewing angle for the reference case.
  • the reflectivity difference between the coatings of the near-edge substrate surfaces and the remainder of the substrate surfaces can be increased, (e.g., the difference between the first and third substrate surfaces and the second and fourth substrate surfaces).
  • this experimental result was compared with previous modeling results on the optimal reflectivity of near-edge substrate surface coating, which is shown in FIG. 19.
  • the modeling results predict the optimal reflectivity difference between the nearby-tiling-edge substrate surface and the other substrate surface is about 5%.
  • the reflectivity difference between the near-edge substrate surface and the other substrate surfaces is -2.5% in the experiment. This suggests further increasing the reflectivity of the near-edge substrate coating by about 2.5% to get optimal seam visibility mitigation when the same substrate surface coating is used.

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Abstract

Dispositif d'affichage optique comprenant une plaque de base et une pluralité de cartes à DEL en mosaïque disposées sur cette dernière. La plaque de base et/ou les cartes à DEL peuvent être revêtues d'un ou plusieurs matériaux de revêtement pour ajuster une réflectivité relative entre la plaque de base et les cartes à DEL afin de réduire à un minimum l'intensité de la lumière réfléchie au niveau de l'espace entre les cartes à DEL en mosaïque en raison de la réflectance au niveau de la plaque de base.
PCT/US2023/031007 2022-09-08 2023-08-24 Mosaïque d'affichage à visibilité de joint réduite WO2024054357A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6567138B1 (en) * 1999-02-15 2003-05-20 Rainbow Displays, Inc. Method for assembling a tiled, flat-panel microdisplay array having imperceptible seams
US20190122592A1 (en) * 2017-10-25 2019-04-25 Samsung Electronics Co., Ltd. Led panel and display apparatus having the same
US20200295120A1 (en) * 2019-03-12 2020-09-17 X Display Company Technology Limited Tiled displays with black-matrix support screens
WO2021221905A1 (fr) * 2020-04-29 2021-11-04 Corning Incorporated Dispositifs d'affichage avec composants en carreaux
KR20210141146A (ko) * 2020-05-15 2021-11-23 삼성전자주식회사 디스플레이 모듈을 포함하는 디스플레이 장치 및 그 제조 방법

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6567138B1 (en) * 1999-02-15 2003-05-20 Rainbow Displays, Inc. Method for assembling a tiled, flat-panel microdisplay array having imperceptible seams
US20190122592A1 (en) * 2017-10-25 2019-04-25 Samsung Electronics Co., Ltd. Led panel and display apparatus having the same
US20200295120A1 (en) * 2019-03-12 2020-09-17 X Display Company Technology Limited Tiled displays with black-matrix support screens
WO2021221905A1 (fr) * 2020-04-29 2021-11-04 Corning Incorporated Dispositifs d'affichage avec composants en carreaux
KR20210141146A (ko) * 2020-05-15 2021-11-23 삼성전자주식회사 디스플레이 모듈을 포함하는 디스플레이 장치 및 그 제조 방법

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